Display device having an emission layer

ABSTRACT

A display device includes signal lines and pixels connected thereto. A first pixel includes a first transistor including a first gate electrode, a first channel region overlapping the first gate electrode, a first source region, and a second drain region facing the first source region, with the first channel region interposed between the first source region and the second drain region. A third transistor includes a third gate electrode, a third channel region overlapping the third gate electrode, a third drain region connected to the first gate electrode, and a third source region facing the third drain region with the third channel region interposed between the third source region and the third drain region. A shielding part overlaps a boundary between the third source region and the third channel region and does not overlap a boundary between the third drain region and the third channel region.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Continuation of co-pending U.S. patent application Ser. No. 16/421,885, filed on May 24, 2019, which is a Continuation of U.S. patent application Ser. No. 15/655,790, filed on Jul. 20, 2017 which claims priority to and the benefit of Korean Patent Application No. 10-2016-0131465 filed in the Korean Intellectual Property Office on Oct. 11, 2016, the entire contents of which are incorporated by reference herein.

TECHNICAL FIELD

The present disclosure relates to a display device, and more specifically, relates to a display device including an emission layer.

DISCUSSION OF THE RELATED ART

A display device for displaying an image includes a plurality of pixels. For example, a pixel of an organic light emitting diode (OLED) display may include an organic light emitting diode having a cathode, an anode, and an organic emission layer disposed therebetween. A plurality of transistors and at least one capacitor for driving the organic light emitting diode may also be included therein.

In the OLED display, electrons injected from the cathode and holes injected from the anode are combined in the organic emission layer to form an exciton. As the exciton returns to a relaxed state within the organic emission layer, energy is emitted in the form of light.

The plurality of transistors include at least one switching transistor and a driving transistor. At least one switching element may receive a data signal, which depends on a scan signal, and may transmit a voltage to the driving transistor. The driving transistor is directly or indirectly connected to the organic light emitting diode to control an amount of current transmitted to the organic light emitting diode, thereby emitting light of a desired luminance through each pixel.

The capacitor is connected to a driving gate electrode of the driving transistor, thereby maintaining a voltage of the driving gate electrode.

SUMMARY

A display device includes a plurality of signal lines and a plurality of pixels connected to the plurality of signal lines. A first pixel of the plurality of pixels includes a first transistor including a first gate electrode, a first channel region at least partially overlapping the first gate electrode in a plan view, a first source region, and a second drain region facing the first source region, with the first channel region interposed between the first source region and the second drain region. A third transistor includes a third gate electrode, a third channel region at least partially overlapping the third gate electrode in the plan view, a third drain region connected to the first gate electrode, and a third source region facing the third drain region with the third channel region interposed between the third source region and the third drain region. A shielding part at least partially overlaps a boundary between the third source region and the third channel region and does not overlap a boundary between the third drain region and the third channel region in the plan view.

A display device includes a plurality of signal lines and a plurality of pixels connected to the plurality of signal lines. A first pixel included in the plurality of pixels includes a first transistor including a first gate electrode, a first channel region at least partially overlapping the first gate electrode in the plan view, and a first source region and a second drain region facing each other with the first channel region interposed therebetween. A third transistor includes a third gate electrode, a third channel region at least partially overlapping the third gate electrode in the plan view, a third drain region connected to the first gate electrode, and a third source region facing the third drain region with the third channel region interposed therebetween. A shielding part at least partially overlaps at least one of a boundary between the third source region and the third channel region and a boundary between the third drain region and the third channel region. The shielding part is configured to transmit an initialization voltage.

A display device includes a plurality of signal lines and a plurality of pixels connected to the plurality of signal lines. A first pixel included in the plurality of pixels includes a first transistor including a first gate electrode, a first channel region at least partially overlapping the first gate electrode in the plan view, and a first source region and a second drain region facing each other with the first channel region interposed therebetween. A third transistor includes a third gate electrode, a third channel region at least partially overlapping the third gate electrode in the plan view, a third drain region connected to the first gate electrode, and a third source region facing the third drain region with the third channel region interposed therebetween. A shielding part at least partially overlaps at least one of a boundary between the third source region and the third channel region and a boundary between the third drain region and the third channel region. The shielding part is configured to transmit an initialization voltage.

An organic light emitting diode (OLED) display device includes a display substrate. A plurality of pixels is disposed on the display substrate. Each of the plurality of pixels includes a transistor. A plurality of signal lines is disposed on the display substrate and is connected to the plurality of pixels. The plurality of signal lines at least partially covers each transistor of the plurality of pixels.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the present disclosure and many of the attendant aspects thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:

FIG. 1 is an equivalent circuit diagram illustrating one pixel of a display device according to an exemplary embodiment of the present invention;

FIG. 2 is a timing diagram illustrating driving signals of a display device according to an exemplary embodiment;

FIG. 3 is a top plan view illustrating a plurality of pixels of a display device according to an exemplary embodiment of the present invention;

FIG. 4 to FIG. 6 are top plan views illustrating one pixel among a plurality of pixels shown in FIG. 3;

FIG. 7 is a cross-sectional view illustrating a display device shown in FIG. 4 taken along a line VII-VII;

FIG. 8 is a cross-sectional view illustrating a display device shown in FIG. 4 taken along a line VIII-VIII′;

FIG. 9 is a top plan view illustrating a plurality of pixels of a display device according to an exemplary embodiment of the present invention;

FIG. 10 is a top plan view illustrating one pixel of a display device according to an exemplary embodiment of the present invention;

FIG. 11 is a cross-sectional view illustrating a display device shown in FIG. 10 taken along a line XI-XI′;

FIG. 12 is a top plan view illustrating one pixel of a display device according to an exemplary embodiment of the present invention;

FIG. 13 is a cross-sectional view illustrating a display device shown in FIG. 12 taken along a line XIII-XIII′;

FIG. 14 is a cross-sectional view illustrating a display device shown in FIG. 12 taken along a line XIV-XIV′; and

FIG. 15 is a top plan view illustrating one pixel of a display device according to an exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present invention will be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

The same reference numerals may be used to designate the same or similar constituent elements through the entire specification and the drawings.

In addition, the size and thickness of each configuration shown in the drawings, such as layers, films, panels, regions, etc. may be exaggerated for better understanding and ease of description, but the present invention is not limited thereto.

It will be understood that when an element such as a layer, film, region, or substrate is referred to as being “on” another element, it can be directly on the other element or intervening elements may also be present.

A display device according to an exemplary embodiment of the present invention will be described below with reference to FIG. 1.

FIG. 1 is an equivalent circuit diagram of one pixel of a display device according to an exemplary embodiment of the present invention.

Referring to FIG. 1, a display device, according to an exemplary embodiment of the present invention, includes a plurality of pixels PX displaying an image in response to an image signal and a plurality of signal lines 151, 152, 153, 154, 171, and 172. One pixel PX may include a plurality of transistors T1, T2, T3, T4, T5, T6, and T7 connected to the plurality of signal lines 151, 152, 153, 154, 171, and 172, a capacitor Cst, and at least one light emitting diode (LED) ED. According to an exemplary embodiment of the present invention, an example in which one pixel PX includes one light emitting diode (LED) ED is mainly described.

The signal lines 151, 152, 153, 154, 171, and 172 may include a plurality of scan lines 151, 152, and 154, a plurality of control lines 153, a plurality of data lines 171, and a plurality of driving voltage lines 172.

The plurality of scan lines 151, 152, and 154 may respectively transmit scan signals GWn, GIn, and GI(n+1). The scan signals GWn, GIn, and GI(n+1) may transmit a gate-on voltage and a gate-off voltage for turning-on/turning-off the transistors T2, T3, T4, and T7 included in the pixel PX.

The scan lines 151, 152, and 154 connected to one pixel PX may include a first scan line 151 transmitting a scan signal GWn, a second scan line 152 transmitting a scan signal GIn having the gate-on voltage at a different time from the first scan line 151, and a third scan line 154 transmitting the scan signal GI(n+1). According to an exemplary embodiment of the present invention, an example in which the second scan line 152 transmits the gate-on voltage at an earlier time than the first scan line 151 will be mainly described. For example, when the scan signal GWn is the n-th scan signal Sn (where n is a positive integer) among scan signals applied during one frame, the scan signal GIn may be a previous scan signal such as an (n−1)-th scan signal S(n−1), and the scan signal GI(n+1) may be an n-th scan signal Sn. However, the invention is not limited thereto, and the scan signal GI(n+1) may be a scan signal other than the n-th scan signal Sn.

The control line 153 may transmit a control signal. For example, the control line 153 may transmit a light emitting control signal controlling light emitting of the light emitting diode (LED) ED included in the pixel PX. The control signal transmitted by the control line 153 may transmit the gate-on voltage and the gate-off voltage and may have a different waveform from the scan signal(s) transmitted by the scan lines 151, 152, and 154.

The data line 171 may transmit a data signal Dm and the driving voltage line 172 may transmit a driving voltage ELVDD. The data signal Dm may have different voltage levels in response to the image signal input to the display device, and the driving voltage ELVDD may have a substantially constant level.

The display device may further include a driver transmitting the signals to the plurality of signal lines 151, 152, 153, 154, 171, and 172. For example, the driver may include a scan driver transmitting the scan signal to the plurality of scan line 151, 152, and 154 and a data driver transmitting the data signal to the data line 171. At least one driver may be formed directly on a display panel of the display device along with the plurality of transistors T1-T7 included in the pixel PX. Alternatively, at least one driver may be attached on the display panel in a type of at least one driving circuit chip. Alternatively, at least one driver may be attached on a printed circuit film connected to the display panel to transmit the signals to the display panel. The driver or the printed circuit film may be disposed around a display area of the display panel, in which the plurality of pixels PX are disposed.

The transistors T1, T2, T3, T4, 15, T6, and T7 may include a first transistor T1, a second transistor T2, a third transistor T3, a fourth transistor T4, a fifth transistor T5, a sixth transistor T6, and a seventh transistor T7.

The first scan line 151 may transmit the scan signal GWn to the second transistor T2 and the third transistor T3, the second scan line 152 may transmit the scan signal GIn to the fourth transistor T4, the third scan line 154 may transmit the scan signal GI(n+1) to the seventh transistor T7, and the control line 153 may transmit the light emitting control signal EM to the fifth transistor T5 and the sixth transistor T6.

A gate electrode G1 of the first transistor T1 is connected to one terminal Cst1 of the capacitor Cst through a driving gate node GN, a source electrode S1 of the first transistor T1 is connected to the driving voltage line 172 through the fifth transistor T5, and a drain electrode D1 of the first transistor T1 is electrically connected to an anode of the light emitting diode (LED) ED via the sixth transistor T6. The first transistor T1 receives a data signal Dm transmitted by the data line 171 in response to a switching operation of the second transistor T2 to supply a driving current Id to the light emitting diode (LED) ED.

A gate electrode G2 of the second transistor T2 is connected to the first scan line 151, a source electrode S2 of the second transistor T2 is connected to the data line 171, and a drain electrode D2 of the second transistor T2 is connected to the source electrode S1 of the first transistor T1 and to the driving voltage line 172 via the fifth transistor T5. The second transistor T2 is turned on in response to the scan signal GWn transmitted through the first scan line 151 such that the data signal Dm transmitted from the data line 171 may be transmitted to the source electrode S1 of the first transistor T1.

A gate electrode G3 of the third transistor T3 is connected to the first scan line 151, and a source electrode S3 of the third transistor T3 is connected to the drain electrode D1 of the first transistor T1 and to the anode of the organic light emitting diode OLED via the sixth transistor T6. A drain electrode D3 of the third transistor T3 is connected to a drain electrode D4 of the fourth transistor T4, one terminal Cst1 of the capacitor Cst, and the gate electrode G1 of the first transistor T1. The third transistor T3 is turned on in response to the scan signal GWn transmitted through the first scan line 151 to diode-connect the first transistor T1 by connecting the gate electrode G1 and the drain electrode D1 of the first transistor T1 to each other.

A gate electrode G4 of the fourth transistor T4 is connected to the second scan line 152, a source electrode S4 of the fourth transistor T4 is connected to a terminal of an initialization voltage Vint, and a drain electrode D4 of the fourth transistor T4 is connected to one terminal Cst1 of the capacitor Cst and the gate electrode G1 of the first transistor T1 through the drain electrode D3 of the third transistor T3. The fourth transistor T4 is turned on in response to the previous scan signal GIn transmitted through the previous scan line 152 to transmit the initialization voltage Vint to the gate electrode G1 of the first transistor T1, thereby performing an initialization operation initializing the voltage of the gate electrode G1 of the first transistor T1.

A gate electrode G5 of the fifth transistor T5 is connected to the control line 153, a source electrode S5 of the fifth transistor T5 is connected to the driving voltage line 172, and a drain electrode D5 of the fifth transistor T5 is connected to the source electrode S1 of the first transistor T1 and the drain electrode D2 of the second transistor T2.

A gate electrode G6 of the sixth transistor T6 is connected to the control line 153, a source electrode S6 of the sixth transistor T6 is connected to the drain electrode D1 of the first transistor T1 and the source electrode S3 of the third transistor T3, and a drain electrode D6 of the sixth transistor T6 is electrically connected to the anode of the organic light emitting diode (LED) ED. The fifth transistor T5 and the sixth transistor T6 are simultaneously turned on in response to the light emitting control signal EM transmitted thorough the control line 153, and thus the driving voltage ELVDD is compensated by the diode-connected driving transistor T1 and may be transmitted to the light emitting diode (LED) ED, after being compensated by the diode-connected driving transistor T1.

A gate electrode G7 of the seventh transistor T7 is connected to the third scan line 154, a source electrode S7 of the seventh transistor T7 is connected to the drain electrode D6 of the sixth transistor T6 and the anode of the light emitting diode (LED) ED, and a drain electrode D7 of the seventh transistor T7 is connected to the terminal of the initialization voltage Vint and the source electrode S4 of the fourth transistor T4. Alternatively, the gate electrode G7 of the seventh transistor T7 may be connected to a separate control line.

The transistors T1, T2, T3, T4, 15, T6, and T7 may each be a P-type channel transistor such as a PMOS, however the present invention is not limited thereto, and at least one among the transistors T1, T2, T3, T4, T5, T6, and T7 may be an N-type channel transistor.

One terminal Cst1 of the capacitor Cst is connected to the gate electrode G1 of the first transistor T1 as described above, and the other terminal Cst2 thereof is connected to the driving voltage line 172. A cathode of the light emitting diode (LED) ED may be connected to a common voltage ELVSS terminal transmitting a common voltage ELVSS to receive the common voltage ELVSS.

The structure of the pixel PX, according to an exemplary embodiment of the present invention, is not limited to the structure shown in FIG. 1, and a number of transistors and a number of capacitors that are included in one pixel PX and a connection relationship thereof may be variously modified.

Next, a driving method of the display device, according to an exemplary embodiment of the present invention, will be described with reference to FIG. 2 along with FIG. 1. In the present description, an example in which the transistors T1, T2, T3, T4, T5, T6, and T7 are P-type channel transistors is described, and an operation of one frame will be described.

Referring to FIG. 2, in one frame, the scan signals . . . , S(n−2), S(n−1), Sn, . . . of a low level may be sequentially applied to the plurality of first scan lines 151 connected to the plurality of pixels PX.

A scan signal GIn of a low level is supplied through the second scan line 152 for an initialization period. For example, the scan signal GIn may be a (n−1)-th scan signal S(n−1). Then, the fourth transistor T4 is turned on in response to the scan signal GIn of the low level, the initialization voltage Vint is connected to the gate electrode G1 of the first transistor T1 through the fourth transistor T4, and the driving transistor T1 is initialized by the initialization voltage Vint.

Subsequently, if the scan signal GWn of the low level is supplied through the first scan line 151 during a data programming and compensation period, the second transistor T2 and the third transistor T3 are turned on in response to the scan signal GWn of the low level. For example, the scan signal GWn may be an (n-th) scan signal Sn. In this case, the first transistor T1 is diode-connected by the turned-on third transistor T3 and is biased in a forward direction. Accordingly, a compensation voltage (Dm+Vth, Vth is a negative value) decreased by a threshold voltage Vth of the first transistor T1 from the data signal Dm supplied from the data line 171 is applied to the gate electrode G1 of the first transistor T1. For example, the gate voltage applied to the gate electrode G1 of the first transistor T1 may become the compensation voltage (Dm+Vth).

The driving voltage ELVDD and the compensation voltage (Dm+Vth) may be respectively applied to both terminals of the capacitor Cst, and the capacitor Cst may be charged with a charge corresponding to a voltage difference of both terminals.

Next, the light emitting control signal EM supplied from the control line 153 is changed from the high level to the low level during a light emitting period. A time when the light emitting control signal EM is changed from the high level to the low level may be after the scan signal GWn is applied to all first scan lines 151 in one frame. Thus, during the light emitting period, the fifth transistor T5 and the sixth transistor T6 are turned on by the light emitting control signal EM of the low level. Thus, a driving current Id is generated in response to the voltage difference between the gate voltage of the gate electrode G1 of the first transistor T1 and the driving voltage ELVDD, and the driving current Id is supplied to the light emitting diode ED through the sixth transistor T6, thereby a current led flows to the light emitting diode ED. The gate-source voltage Vgs of the first transistor T1 is maintained as ‘(Dm+Vth)-ELVDD’ by the capacitor Cst during the light emission period, and in response to a current-voltage relationship of the first transistor T1, the driving current Id may be proportional to a square ‘(Dm-ELVDD)²’ of a value obtained by subtracting the threshold voltage from the driving gate-source voltage. Accordingly, the driving current Id may be determined regardless of the threshold voltage Vth of the first transistor T1.

During an initialization period, the seventh transistor T7 receives the scan signal GI(n+1) of the low level through the third scan line 154 to be turned on. The scan signal GI(n+1) may be an n-th scan signal Sn. In this case, the seventh transistor T7 may be simultaneously turned-on with the second and third transistors T2 and T3. A part of the driving current Id may flow out through the seventh transistor T7 as a bypass current Ibp by the turned-on seventh transistor T7.

Next, an example of the detailed structure of the display device, according to an exemplary embodiment of the present invention, will be described with reference to FIG. 3 to FIG. 8 along with FIG. 1 and FIG. 2.

For ease of understanding, a plane structure of the display device, according to an exemplary embodiment of the present invention, is firstly described and then a cross-sectional structure is described in detail.

FIG. 3 is a top plan view of a plurality of pixels of a display device, according to an exemplary embodiment of the present invention, FIG. 4 is a top plan view of a region indicated by ‘A’ in FIG. 3, FIG. 5 is a top plan view of a region indicated by ‘B’ in FIG. 3, and FIG. 6 is a top plan view of a region indicated by ‘C’ in FIG. 3.

The plurality of pixels PX included in the display device, according to an exemplary embodiment of the present invention, may respectively display a predetermined color. The plurality of pixels, for example, may include a red pixel R representing a red color, a green pixel G representing a green color, and a blue pixel B representing a blue color. FIG. 3 shows the red pixel R, the green pixel G, and the blue pixel B that are adjacent to each other. Alternatively, at least one among the red pixel R, the green pixel G, and the blue pixel B may represent different colors.

The display device, according to an exemplary embodiment of the present invention, may include a first conductive layer including the first scan line 151 transmitting the scan signal GWn, the second scan line 152 transmitting the scan signal Gin, the third scan line 154 transmitting the scan signal GI(n+1), and the control line 153 transmitting the light emitting control signal EM. The first conductive layer is disposed on one surface of a substrate 110 in the cross-sectional view, and may include the same material and may be disposed on the same layer.

The substrate 110 may include an inorganic or organic insulating material such as glass, plastic, etc., and may be flexible.

The plurality of scan lines 151, 152, and 154 and the control line 153 may extend in the same direction (e.g., a horizontal direction in FIG. 3) in the plan view. The first scan line 151 may be disposed between the second scan line 152 and the control line 153 in the plan view. When viewing the entire display device, the third scan line 154 as a scan line substantially such as the second scan line 152 may transmit the scan signal GI(n+1) next to the scan signal GIn transmitted by the second scan line 152. As described above, when the first scan line 151 transmits the n-th scan signal Sn, the third scan line 154 may also transmit the n-th scan signal Sn.

The display device, according to an exemplary embodiment of the present invention, may further include a second conductive layer including a storage line 156 and an initialization voltage line 159. The second conductive layer is disposed on a different layer from the first conductive layer in the cross-sectional view. For example, the second conductive layer may be disposed on the first conductive layer, may include the same material, and may be disposed in the same layer.

The storage line 156 and the initialization voltage line 159 may extend in primarily the same direction (e.g., the horizontal direction in FIG. 3) in the plan view.

The storage line 156 may be disposed between the first scan line 151 and the control line 153 in the plan view and may include an extension part 157 disposed in each pixel R, G, and B. The extension part 157 is connected to the driving voltage line 172 through a contact hole 68 thereby receiving the driving voltage ELVDD. The extension part 157 may have an opening 51.

The initialization voltage line 159 may transmit the initialization voltage Vint and may be disposed between the third scan line 154 and the control line 153 in the plan view, but the position is not limited thereto.

The display device, according to an exemplary embodiment of the present invention, may further include a third conductive layer including the data line 171 transmitting the data signal Dm and the driving voltage line 172 transmitting the driving voltage ELVDD. The third conductive layer is disposed at the different layer from the first conductive layer and the second conductive layer in the cross-sectional view. For example, the third conductive layer may be disposed on the second conductive layer in the cross-sectional view, may include the same material, and may be disposed in the same layer.

The data line 171 and the driving voltage line 172 may extend primarily in the same direction (e.g., the vertical direction in FIG. 3) in the plan view, and may cross the plurality of scan lines 151, 152, and 154, the control line 153, the initialization voltage line 159, and the storage line 156.

Each of the pixels R, G, and B may include the plurality of transistors T1, T2, T3, T4, T5, T6, and T7 connected to the scan lines 151, 152, and 154, the control line 153, the data line 171, and the driving voltage line 172, the capacitor Cst, and the light emitting diode (LED) ED.

Each channel of the plurality of transistors T1, T2, T3, T4, T5, T6, and T7 for one pixel PX may be formed in one active pattern 130, and the active pattern 130 may be curved in various shapes. The active pattern 130 may include a semiconductor material such as a polysilicon or an oxide semiconductor.

The active pattern 130 may be disposed between the substrate 110 and the first conductive layer in the cross-sectional view.

The active pattern 130 includes channel regions 131 a, 131 b, 131 c_1, 131 c_2, 131 d_1, 131 d_2, 131 e, 131 f, and 131 g forming each channel of the transistors T1, T2, T3, T4, T5, T6, and T7 and a conductive region. For example, the third transistor T3 and the fourth transistor T4 may have a dual gate structure. In this case, the third transistor T3 includes two channel regions 131 c_1 and 131 c_2, and the fourth transistor T4 also includes two channel regions 131 d_1 and 131 d_2.

The conductive region of the active pattern 130 is disposed at both sides of each of the channel regions 131 a, 131 b, 131 c_1, 131 c_2, 131 d_1, 131 d_2, 131 e, 131 f, and 131 g, and has a higher carrier concentration than the carrier concentration of the channel regions 131 a, 131 b, 131 c_1, 131 c_2, 131 d_1, 131 d_2, 131 e, 131 f, and 131 g. In the active pattern 130, most of the rest of the portion except for the channel regions 131 a, 131 b, 131 c_1, 131 c_2, 131 d_1, 131 d_2, 131 e, 131 f, and 131 g may be the conductive region. A pair of conductive regions disposed at both sides of the channel regions 131 a, 131 b, 131 c_1, 131 c_2, 131 d_1, 131 d_2, 131 e, 131 f, and 131 g of each of the transistors T1, T2, T3, T4, T5, T6, and T7 as a source region and a drain region of the corresponding transistors T1, T2, T3, T4, T5, T6, and T7 may function as the source electrode and the drain electrode.

The first transistor T1 includes a channel region 131 a, a source region 136 a and a drain region 137 a that are conductive regions of the active pattern 130 disposed at respective sides of the channel region 131 a, and a driving gate electrode 155 a overlapping the channel region 131 a in the plan view.

The channel region 131 a of the first transistor T1 may be bent at least one time. For example, the channel region 131 a may have a meandering shape or a zigzag shape. FIG. 3 to FIG. 6 show an example in which the channel region 131 a has a U-shape that is alternately disposed up-facing and down-facing.

The source region 136 a and the drain region 137 a are connected to respective sides of the channel region 131 a in the plan view.

The driving gate electrode 155 a may be included in the first conductive layer and may be connected to a connector 174 through a contact hole 61. The contact hole 61 may be disposed inside the opening 51 in a plan view. The connector 174 may be included in the third conductive layer in the cross-sectional view. The connector 174 may be elongated in a direction primarily parallel to a direction in which the data line 171 extends. The connector 174 corresponds to a driving gate node GN shown in a circuit diagram of FIG. 1 along with the driving gate electrode 155 a.

The second transistor T2 includes the channel region 131 b, a source region 136 b and a drain region 137 b that are conductive regions of the active pattern 130 disposed at respective sides of the channel region 131 b, and a gate electrode 155 b overlapping the channel region 131 b in the plan view. The gate electrode 155 b is a part of the first scan line 151. The source region 136 b is disposed upward based on the first scan line 151 in the plan view, is connected to the channel region 131 b, and is connected to the data line 171 through a contact hole 62. The drain region 137 b is disposed downward based on the first scan line 151 in the plan view, is connected to the channel region 131 b, and is connected to the source region 136 a of the first transistor T1.

The third transistor T3 may be formed of two parts to prevent the leakage current. For example, the third transistor T3 may include an upper third transistor T3_1 and a lower third transistor T3_2 adjacent to each other and connected to each other.

The upper third transistor T3_1 includes the channel region 131 c_1 overlapping the first scan line 151 in the plan view, a source region 136 c_1 and a drain region 137 c_1 that are conductive regions of the active pattern 130 disposed at respective sides of the channel region 131 c_1, and a gate electrode 155 c_1 overlapping the channel region 131 c_1. The gate electrode 155 c_1 may be a part of a protrusion of the first scan line 151. The drain region 137 c_1 is disposed upward based on the first scan line 151 in the plan view, and is connected to the connector 174 through a contact hole 63.

The lower third transistor T3_2 includes the channel region 131 c_2 overlapping the first scan line 151 in the plan view, a source region 136 c_2 and a drain region 137 c_2 that are conductive regions of the active pattern 130 disposed at respective sides of the channel region 131 c_2, and a gate electrode 155 c_2 overlapping the channel region 131 c_2. The gate electrode 155 c_2 is a part of the first scan line 151. The source region 136 c_2 of the lower third transistor T3_2 is connected to the drain region 137 a of the first transistor T1, and the drain region 137 c_2 is connected to the upper source region 136 c_1 of the third transistor T3_1.

The fourth transistor T4 may also be formed of two parts to prevent the leakage current. For example, the fourth transistor T4 may include a left fourth transistor T4_1 and a right fourth transistor T4_2 adjacent to each other and connected to each other.

The left fourth transistor T4_1 includes the channel region 131 d_1 overlapping the second scan line 152 in the plan view, a source region 136 d_1 and a drain region 137 d_1 that are the conductive region of the active pattern 130 disposed at respective sides of the channel region 131 d_1, and a gate electrode 155 d_1 overlapping the channel region 131 d_1. The gate electrode 155 d_1 is a part of the second scan line 152. The drain region 137 d_1 is disposed downward based on the second scan line 152 in the plan view, is connected to the drain region 137 c_1 of the upper third transistor T3_1, and is connected to the connector 174 through the contact hole 63.

The right fourth transistor T4_2 includes the channel region 131 d_2 overlapping the second scan line 152 in the plan view, a source region 136 d_2 and a drain region 137 d_2 that are the conductive regions of the active pattern 130 disposed at respective sides of the channel region 131 d_2, and a gate electrode 155 d_2 overlapping the channel region 131 d_2. The gate electrode 155 d_2 is a part of the second scan line 152. The drain region 137 d_2 is connected to the source region 136 d_1 of the left fourth transistor T4_1, and the source region 136 d_2 is connected to a connector 175 through a contact hole 65.

The connector 175 may be included in a second conductive layer or a third conductive layer in the cross-sectional view. When the connector 175 is included in the third conductive layer, the connector 175 is electrically connected to the initialization voltage line 159 through a contact hole 64. When the connector 175 is included in the second conductive layer, the connector 175 is disposed on the same layer as the initialization voltage line 159 in the cross-sectional view, and may be connected to the initialization voltage line 159.

A boundary between the channel region 131 d_1 of the left fourth transistor T4_1 connected to the connector 174 transmitting a voltage of the driving gate electrode 155 a and the source region 136 d_1 and a boundary between the and channel region 131 d_1 and the drain region 137 d_1 may each be covered by the driving voltage line 172 along with the channel region 131 d_1 in the plan view. The channel region 131 d_1, the boundary between the channel region 131 d_1 and the source region 136 d_1, and the boundary between the channel region 131 d_1 and the drain region 137 d_1 overlaps the driving voltage line 172 in the plan view, and may be disposed in a plane region of the driving voltage line 172. In the plan view, a width of each of the channel region 131 d_1, the source region 136 d_1, and the drain region 137 d_1 of the left fourth transistor T4_1 in the horizontal direction is smaller than a width of the driving voltage line 172 in the horizontal direction, and the channel region 131 d_1, the source region 136 d_1, and the drain region 137 d_1 may all be disposed within the region of the driving voltage line 172.

Accordingly, although external light (e.g., such as the light shown in FIG. 8) is incident to the display device, the external light is blocked by the driving voltage line 172 such that the external light may be prevented from being incident to the channel region 131 d_1 of the left fourth transistor T4_1. Accordingly, the leakage current that would otherwise be caused by the light is prevented by the left fourth transistor T4_1 directly connected to the driving gate node GN such that the voltage change of the capacitor Cst may be suppressed. A display failure such as a luminance change of the image and a color coordinate change may accordingly be prevented.

There is an upper third transistor T3_1 as one transistor that is directly connected to the connector 174 transmitting the voltage of the driving gate electrode 155 a. The boundary between the channel region 131 c_1 of the upper third transistor T3_1 and the source region 136 c_1 and/or the boundary between the channel region 131 c_1 and the drain region 137 c_1 is covered by a shielding part 176 in the plan view. For example, at least one of the boundary between the channel region 131 c_1 and the source region 136 c_1 and the boundary between the channel region 131 c_1 and the drain region 137 c_1 overlaps the shielding part 176 in the plan view, thereby being disposed in the region of the shielding part 176.

For example, as shown above, the shielding part 176 overlaps the boundary between the channel region 131 c_1 of the upper third transistor T3_1 and the source region 136 c_1 in the plan view. The shielding part 176 might not overlap the boundary of the channel region 131 c_1 of the upper third transistor T3_1 and the drain region 137 c_1 and accordingly, these elements may be spaced apart from the connector 174, in the plan view.

In the plan view, the width WI as a distance from the boundary between the channel region 131 c_1 of the upper third transistor T3_1 and the source region 136 c_1 to one edge of a left or a right of the shielding part 176 may be about 3 micrometers or more, however the width WI it is not limited thereto.

The shielding part 176 may be included in the second conductive layer or the third conductive layer. When the shielding part 176 is included in the third conductive layer, the shielding part 176 may be disposed on the same layer as the connector 175, and may be electrically and physically connected to the connector 175. The shielding part 176 may be spaced apart from the connector 174 connected to the driving gate electrode 155 a by a predetermined distance.

Alternatively, the shielding part 176 may further include a part overlapping the boundary between the channel region 131 c_1 of the upper third transistor T3_1 and the drain region 137 c_1 in the plan view. For example, when the shielding part 176 is disposed on a different layer from the connector 174 in the cross-sectional view, as described above, the shielding part 176 may include a part overlapping the boundary between the channel region 131 c_1 of the upper third transistor T3_1 and the source region 136 c_1 and the boundary between the channel region 131 c_1 and the drain region 137 c_1 in the plan view.

According to an exemplary embodiment of the present invention, although the external light is incident to the display device, the external light is blocked by the shielding part 176 such that the external light may be prevented from being incident through the boundary part between the channel region 131 c_1 of the upper third transistor T3_1 and the source region 136 c_1 and/or the drain region 137 c_1. Accordingly, the leakage current due to the light is prevented by the upper third transistor T3_1 directly connected to the driving gate node GN such that the voltage change of the capacitor Cst may be suppressed, and resultantly a display failure such as a luminance change of the image and a color coordinate change may be prevented.

The fifth transistor T5 includes the channel region 131 e, a source region 136 e and a drain region 137 e that are the conductive regions of the active pattern 130 disposed at respective sides of the channel region 131 e, and a gate electrode 155 e overlapping the channel region 131 e. The gate electrode 155 e is a part of the control line 153. The source region 136 e is disposed downward based on the control line 153 in the plan view, is connected to the channel region 131 e, and is connected to the driving voltage line 172 through a contact hole 67. The drain region 137 e is disposed upward based on the control line 153 in the plan view, is connected to the channel region 131 e, and is connected to the source region 136 a of the first transistor T1.

The sixth transistor T6 includes the channel region 131 f, a source region 136 f and a drain region 137 f that are the conductive regions of the active pattern 130 disposed at respective sides of the channel region 131 f, and a gate electrode 155 f overlapping the channel region 131 f. The gate electrode 155 f is a part of the control line 153. The source region 136 f is disposed upward based on the control line 153 in the plan view, is connected to the channel region 131 f, and is connected to the drain region 137 a of the first transistor T1. The drain region 137 f is disposed downward based on the control line 153 in the plan view, is connected to the channel region 131 f, and is connected to a connector 179 through a contact hole 69. The connector 179 may be included in the third conductive layer in the cross-sectional view.

The seventh transistor T7 includes the channel region 131 g, a source region 136 g and a drain region 137 g that are the conductive regions of the active pattern 130 disposed at respective sides of the channel region 131 g, and a gate electrode 155 g overlapping the channel region 131 g. The gate electrode 155 g is a part of the third scan line 154. The source region 136 g is disposed upward based on the third scan line 154 in the plan view, is connected to the channel region 131 g, and is connected to the drain region 137 f of the sixth transistor T6. The drain region 137 g is disposed downward based on the third scan line 154 in the plan view and is connected to the connector 175 through the contact hole 65, thereby receiving the initialization voltage Vint.

The capacitor Cst may include the driving gate electrode 155 a and the extension part 157 of the storage line 156 overlapping each other in the plan view as two terminals. The capacitor Cst may maintain a voltage difference corresponding to a difference between the extension part 157 of the storage line 156 receiving the driving voltage ELVDD and the voltage of the driving gate electrode 155 a. The extension part 157 of the storage line 156 may have a wider area than the driving gate electrode 155 a in the plan view, and may cover the entire area of the corresponding driving gate electrode 155 a.

The second conductive layer may further include a shielding pattern 158 overlapping the data line 171. The shielding pattern 158 is connected to the driving voltage line 172 through a contact hole 66, thereby receiving the driving voltage ELVDD. The shielding pattern 158 shields between the driving gate node GN and the data line 171, thereby blocking the voltage change of the driving gate node GN by the change of the data signal Dm. According to some exemplary embodiments of the present invention, the shielding pattern 158 may be omitted.

The display device, according to an exemplary embodiment of the present invention, may further include a fourth conductive layer including a plurality of pixel electrodes 191 a, 191 b, and 191 c and a pixel conductive pattern 192. The fourth conductive layer is disposed on a different layer from the first conductive layer, the second conductive layer, and the third conductive layer in the cross-sectional view. For example, the fourth conductive layer may be disposed on the third conductive layer in the cross-sectional view, and may include the same material and may be disposed on the same layer.

The plurality of pixel electrodes 191 a, 191 b, and 191 c may be arranged in a pentile matrix structure. For example, the pixel electrode 191 a of the red pixel R and the pixel electrode 191 c of the blue pixel B may be alternately arranged in the horizontal direction, the pixel electrode 191 a of the red pixel R and the pixel electrode 191 b of the green pixel G may be alternately arranged in a first diagonal direction, and the pixel electrode 191 c of the blue pixel B and the pixel electrode 191 b of the green pixel G may be alternately arranged in a second diagonal direction, which may be different from the first diagonal direction. However, the arrangement of the pixel electrodes 191 a, 191 b, and 191 c is not limited thereto.

The pixel electrode 191 a of the red pixel R may be smaller than the pixel electrode 191 c of the blue pixel B, and the pixel electrode 191 b of the green pixel G may be smaller than the pixel electrode 191 a of the red pixel R.

Each of the pixel electrodes 191 a, 191 b, and 191 c is connected to the connector 179 through a contact hole 89, thereby receiving the voltage.

The pixel conductive pattern 192 may be bent along an edge of the adjacent pixel electrodes 191 a, 191 b, and 191 c, and may include a straight part (192 a, 192 b, and 192 c) and an oblique part 193 that are alternately arranged, respectively. The straight part (192 a, 192 b, and 192 c) may extend to be mainly parallel to the scan lines 151, 152, and 154, and the oblique part 193 may obliquely extend in the extending direction of the straight part (192 a, 192 b, and 192 c). The straight part 192 a may be adjacent on the pixel electrode 191 a of the red pixel R, the straight part 192 b may be adjacent on the pixel electrode 191 b of the green pixel G, and the straight part 192 c may be adjacent on the pixel electrode 191 c of the blue pixel B.

The pixel conductive pattern 192 may transmit the initialization voltage Vint.

Referring to FIG. 3 to FIG. 6, the channel region 131 c_1 of the upper third transistor T3_1, the boundary between the channel region 131 c_1 and the source region 136 c_1, and the boundary between the channel region 131 c_1 and the drain region 137 c_1 are each covered, in the plan view, by the fourth conductive layer.

The channel region 131 c_1 of the upper third transistor T3_1 of the red pixel R, the boundary between the channel region 131 c_1 and the source region 136 c_1, and the boundary between the channel region 131 c_1 and the drain region 137 c_1 each overlap the pixel electrode 191 a in the plan view, thereby being disposed in the plane region of the pixel electrode 191 a. The channel region 131 c_1 of the upper third transistor T3_1 of the green pixel G, the boundary between the channel region 131 c_1 and the source region 136 c_1, and the boundary between the channel region 131 c_1 and the drain region 137 c_1 each overlap the pixel conductive pattern 192 in the plan view, and for example, overlap the straight part 192 b of the pixel conductive pattern 192, thereby being disposed in the plane region of the pixel conductive pattern 192. The channel region 131 c_1 of the upper third transistor T3_1 of the blue pixel B, the boundary between the channel region 131 c_1 and the source region 136 c_1, and the boundary between the channel region 131 c_1 and the drain region 137 c_1 each overlap the pixel electrode 191 c in the plan view, thereby being disposed in the plane region of the pixel electrode 191 c.

Accordingly, although the external light is incident to the display device, the external light is blocked by the fourth conductive layer including the pixel electrodes 191 a, 191 b, and 191 c and the pixel conductive pattern 192 such that the external light may be prevented from being incident into the channel region 131 c_1 of the upper third transistor T3_1. For example, although the boundary between the channel region 131 c_1 and the drain region 137 c_1 of the upper third transistor T3_1 is not covered by the shielding part 176, the boundary between the channel region 131 c_1 and the drain region 137 c_1 along with the channel region 131 c_1 are covered by the fourth conductive layer such that the external light may be blocked from being incident into the channel region 131 c_1 of the upper third transistor T3_1. Accordingly, the leakage current due to the light is blocked in the upper third transistor T3_1 directly connected to the driving gate node GN such that the voltage change of the capacitor Cst may be suppressed.

Next, a cross-sectional structure of the display device, according to an exemplary embodiment of the present invention, will be described in detail with reference to FIG. 3 to FIG. 8.

A buffer layer 120 may be disposed on a substrate 110. The buffer layer 120 blocks impurities from the substrate 110 from contaminating an upper layer above the buffer layer 120. For example, the buffer layer 120 may block impurities from the substrate 110 from penetrating into the active pattern 130 so as to increase desirable characteristics of the active pattern 130 and reduce stress applied to the active pattern 130. The buffer layer 120 may include an inorganic insulating material such as a silicon nitride (SiNx) or a silicon oxide (SiOx), or an organic insulating material. At least part of the buffer layer 120 may be omitted.

The above-described active pattern 130 is disposed on the buffer layer 120, and a first insulating layer 141 is disposed on the active pattern 130.

The above-described first conductive layer may be disposed on the first insulating layer 141. The first conductive layer may include a metal such as copper (Cu), aluminum (Al), molybdenum (Mo), or alloys thereof.

A second insulating layer 142 may be disposed on the first conductive layer and the first insulating layer 141.

The above-described second conductive layer may be disposed on the second insulating layer 142. The second conductive layer may include a metal such as copper (Cu), aluminum (Al), molybdenum (Mo), or alloys thereof.

A third insulating layer 160 may be disposed on the second conductive layer and the second insulating layer 142.

At least one among the first insulating layer 141, the second insulating layer 142, and the third insulating layer 160 may include the inorganic insulating material such as the silicon nitride (SiNx), the silicon oxide (SiOx) and/or the organic insulating material.

The first insulating layer 141, the second insulating layer 142, and the third insulating layer 160 may include the contact hole 61 disposed on the driving gate electrode 155 a, the contact hole 62 disposed on the source region 136 b of the second transistor T2, the contact hole 63 disposed on the drain region 137 c_1 of the upper third transistor T3_1 or the drain region 137 d_1 of the left fourth transistor T4_1, the contact hole 64 disposed on the initialization voltage line 159, the contact hole 65 disposed on the source region 136 d_2 of the right fourth transistor T4_2 or the drain region 137 g of the seventh transistor T7, the contact hole 66 disposed on the shielding pattern 158, the contact hole 67 disposed on the source region 136 e of the fifth transistor T5, the contact hole 68 disposed on the extension part 157 of the storage line 156, and the contact hole 69 disposed on the drain region 137 f of the sixth transistor T6. The contact hole 61 may be formed through the opening 51 of the extension part 157 of the storage line 156.

The above-described third conductive layer may be disposed on the third insulating layer 160. The third conductive layer may include the metal such as copper (Cu), aluminum (Al), molybdenum (Mo), or the alloy thereof.

The extension part 157 of the storage line 156 overlaps the driving gate electrode 155 a with the second insulating layer 142 interposed therebetween, thereby forming the capacitor Cst.

A passivation layer 180 is disposed on the third conductive layer and the third insulating layer 160. The passivation layer 180 may include an organic insulating material such as a polyacrylate resin and a polyimide resin, and an upper surface of the passivation layer 180 may be substantially flat. The passivation layer 180 may include the contact hole 89 disposed on the connector 179.

The above-described fourth conductive layer may be disposed on the passivation layer 180.

A pixel defining layer (PDL) 350 may be disposed on the passivation layer 180 and the fourth conductive layer. The pixel defining layer 350 has an opening 351 formed on the pixel electrodes 191 a, 191 b, and 191 c.

An emission layer 370 is disposed on the pixel electrodes 191 a, 191 b, and 191 c. The emission layer 370 may be disposed in the opening 351. The emission layer 370 may include an organic light emitting material or an inorganic light emitting material.

A common electrode 270 is disposed on the emission layer. The common electrode 270 may also be formed on the pixel defining layer 350, thereby being extended throughout the plurality of pixels.

The pixel electrodes 191 a, 191 b, and 191 c, the emission layer 370, and the common electrode 270 together form the light emitting diode (LED) ED.

An encapsulation layer protecting the light emitting diode (LED) ED may be disposed on the common electrode 270. The encapsulation layer may include the inorganic layer and the organic layer that are alternately stacked.

Next, display devices, according to exemplary embodiments of the present invention, will be described with reference to FIG. 9 to FIG. 15 as well as the above-described drawings. It may be assumed that elements not specifically described below are similar to or identical to corresponding elements that have already been described.

First, referring to FIG. 9, the display device may be mostly the same as the display device according to the above-described exemplary embodiment shown in FIG. 1 to FIG. 8, however, in the present example, the shielding part 176 is spaced apart from the connector 175. The shielding part 176 may be disposed at the same layer as the connector 175, and may be disposed at a different layer in the cross-sectional view.

Next, referring to FIG. 10 and FIG. 11, the display device, according to an exemplary embodiment of the present invention, is mostly the same as the display device according to the above-described exemplary embodiment, however the connector 175 is included in the second conductive layer in the cross-sectional view. Accordingly, the connector 175 is disposed at the same layer as the initialization voltage line 159, and may be physically and electrically connected to the initialization voltage line 159. The shielding part 176 may also be included in the second conductive layer and may be connected to the connector 175.

Next, referring to FIG. 12 to FIG. 14, the display device, according to an exemplary embodiment of the present invention, is mostly the same as the display device according to the above-described exemplary embodiment shown in FIG. 10 and FIG. 11, however the shielding part 176 is spaced apart from the connector 175. The shielding part 176 may be disposed at a different layer from the connector 175 in the cross-sectional view. For example, the shielding part 176 may be included in the second conductive layer.

Next, referring to FIG. 15, the display device, according to an exemplary embodiment of the present invention, is mostly the same as the display device according to the above-described exemplary embodiment, however the second conductive layer including the storage line 156, the initialization voltage line 159, the shielding pattern 158, and the like may be omitted. Also, the second insulating layer 142 may be omitted.

The driving voltage line 172 may include an extension part 173 overlapping the driving gate electrode 155 a, and the extension part 173 and the driving gate electrode 155 a overlap each other with the insulating layer (e.g., the above-described third insulating layer 160) interposed therebetween in the plan view to form the capacitor Cst. Accordingly, space utilization efficiency may be increased and the capacitor Cst of sufficient capacitance may be formed.

The passivation layer 180 may include a contact hole 88 disposed on the connector 175. The pixel conductive pattern 192 may transmit the initialization voltage Vint and may be electrically connected to the connector 175 through the contact hole 88, thereby transmitting the initialization voltage Vint to the connector 175.

While this invention has been described in connection with exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the present invention. 

What is claimed is:
 1. A display device, comprising: a scan line; a driving voltage line for transmitting a driving voltage; a first transistor including a first gate electrode, a first channel region overlapping the first gate electrode in a plan view, and a first source region and a first drain region opposing each other with respect to the first channel region; a second transistor including a second gate electrode, a second channel region overlapping the second gate electrode in the plan view, a second drain region electrically connected to the first gate electrode, and a second source region opposing the second drain region with respect to the second channel region; a third transistor including a third gate electrode of the scan line, a third channel region overlapping the third gate electrode in the plan view, a third drain region electrically connected to the first gate electrode and extending from the second drain region in the plan view, and a third source region opposing the third drain region with respect to the third channel region; and a fourth transistor including a fourth gate electrode of the scan line, a fourth channel region overlapping the fourth gate electrode in the plan view, a fourth drain region extending from the third source region in the plan view, and a fourth source region opposing the fourth drain region with respect to the fourth channel region; a shielding part overlapping a boundary between the second source region and the second channel region, and does not overlap a boundary between the second drain region and the second channel region in the plan view; and a light emitting diode comprising a pixel electrode, a light emitting layer, and a common electrode, wherein the pixel electrode overlaps the boundary between the second source region and the second channel region and the boundary between the second drain region and the second channel region in the plan view, and the driving voltage line overlaps a boundary between the third source region and the third channel region and a boundary between the third drain region and the third channel region in the plan view, and does not overlap a boundary between the fourth source region and the fourth channel region. 